Hello all,<br><br>I have searched on google and found out that lower device should not be mounted which has lead to a lot of confusion. My problem is, I am trying to configure /dev/sda to work with DRBD hence the error "Lower Device Already Claimed". It works well when I use /dev/sdb or unmounted partition. As we all know that in runlevel 3, the / (slash root) cannot be unmounted as it is being used so the question becomes how would I make DRBD work with /dev/sda on which I have / (slash root) mounted.<br>
<br><u><b>What I am trying to do.</b></u><br>I want to mirror one drive over the network with another drive to serve for failover purposes (I believe as DRBD states it is like a RAID1 over the network). the two systems master and slave would run exact configuration both hardware and software.<br>
<br>therefore for test purposes, I have created /dev/sda1 on which / (slash root) resides. This / contains the base structure created by Centos such as <br><br>/<br>/boot<br>/dev<br>/bin<br>/home<br>/etc<br><br>I also have free space that can be partitioned to create /dev/sda2.<br>
<br>Now all programs such as httpd, mysql, vsftpd, webmin, bind, sendmail, dovecot and many others are installed with in the /dev/sda1 as well as the data associated with these programs also resides on the /dev/sda1<br><br>
<u><b>What I don't understand</b></u><br><br>If I use /dev/sda2 which is unmounted partion then what would I need to do in terms of setup to ensure that the entire /dev/sda is replicated or how would I mount the /dev/drbd0 to /<br>
<br>Confusing :D<br><br>Thank you all and I am looking forward to your expert responses, leads, assistance :)<br><br>Sincerely<br><br><br>